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From: Jan Kara <jack@suse.cz>
To: <linux-fsdevel@vger.kernel.org>
Cc: amir73il@gmail.com, Jan Kara <jack@suse.cz>
Subject: [PATCH 2/2] fsnotify: Protect bail out path of fsnotify_add_mark_locked() properly
Date: Tue, 31 Oct 2017 10:33:42 +0100	[thread overview]
Message-ID: <20171031093342.25216-3-jack@suse.cz> (raw)
In-Reply-To: <20171031093342.25216-1-jack@suse.cz>

When fsnotify_add_mark_locked() fails it cleans up the mark it was
adding. Since the mark is already visible in group's list, we should
protect update of mark->flags with mark->lock. I'm not aware of any real
issues this could cause (since we also hold group->mark_mutex) but
better be safe and obey locking rules properly.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/notify/mark.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 9991f8826734..47a827975b58 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -599,9 +599,11 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, struct inode *inode,
 
 	return ret;
 err:
+	spin_lock(&mark->lock);
 	mark->flags &= ~(FSNOTIFY_MARK_FLAG_ALIVE |
 			 FSNOTIFY_MARK_FLAG_ATTACHED);
 	list_del_init(&mark->g_list);
+	spin_unlock(&mark->lock);
 	atomic_dec(&group->num_marks);
 
 	fsnotify_put_mark(mark);
-- 
2.12.3

  parent reply	other threads:[~2017-10-31  9:34 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-31  9:33 [PATCH 0/2] dnotify: Fix ENOMEM handling Jan Kara
2017-10-31  9:33 ` [PATCH 1/2] dnotify: Handle errors from fsnotify_add_mark_locked() in fcntl_dirnotify() Jan Kara
2017-10-31 12:11   ` Amir Goldstein
2017-10-31 15:45     ` Jan Kara
2017-10-31 16:15       ` Jan Kara
2017-10-31 16:28         ` Amir Goldstein
2017-10-31  9:33 ` Jan Kara [this message]
2017-10-31 12:26   ` [PATCH 2/2] fsnotify: Protect bail out path of fsnotify_add_mark_locked() properly Amir Goldstein
2017-10-31 12:50     ` Greg KH
2017-10-31 12:57       ` Amir Goldstein
2017-10-31 13:40         ` Greg KH
2017-10-31 16:10     ` Jan Kara

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